ports/rxv1/gnu/src/tx_initialize_low_level.S


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;/***************************************************************************
; * Copyright (c) 2024 Microsoft Corporation
; *
; * This program and the accompanying materials are made available under the
; * terms of the MIT License which is available at
; * https://opensource.org/licenses/MIT.
; *
; * SPDX-License-Identifier: MIT
; **************************************************************************/
;
;
;/**************************************************************************/
;/**************************************************************************/
;/**                                                                       */
;/** ThreadX Component                                                     */
;/**                                                                       */
;/**   Initialize                                                          */
;/**                                                                       */
;/**************************************************************************/
;/**************************************************************************/
;

    .text

;
;/**************************************************************************/
;/*                                                                        */
;/*  FUNCTION                                               RELEASE        */
;/*                                                                        */
;/*    _tx_initialize_low_level                             RXv1/GNURX     */
;/*                                                           6.1.11       */
;/*  AUTHOR                                                                */
;/*                                                                        */
;/*    William E. Lamie, Microsoft Corporation                             */
;/*                                                                        */
;/*  DESCRIPTION                                                           */
;/*                                                                        */
;/*    This function is responsible for any low-level processor            */
;/*    initialization, including setting up interrupt vectors, setting     */
;/*    up a periodic timer interrupt source, saving the system stack       */
;/*    pointer for use in ISR processing later, and finding the first      */
;/*    available RAM memory address for tx_application_define.             */
;/*                                                                        */
;/*  INPUT                                                                 */
;/*                                                                        */
;/*    None                                                                */
;/*                                                                        */
;/*  OUTPUT                                                                */
;/*                                                                        */
;/*    None                                                                */
;/*                                                                        */
;/*  CALLS                                                                 */
;/*                                                                        */
;/*    None                                                                */
;/*                                                                        */
;/*  CALLED BY                                                             */
;/*                                                                        */
;/*    _tx_initialize_kernel_enter           ThreadX entry function        */
;/*                                                                        */
;/**************************************************************************/
    .global __tx_initialize_low_level
__tx_initialize_low_level:

;
;    /* Save the first available memory address.  */
;    _tx_initialize_unused_memory =  (VOID_PTR) &free_mem_start;
;
    MOV.L    #_end, R1                           ; Pickup unused memory address
    MOV.L    #__tx_initialize_unused_memory, R2
    MOV.L    R1,[R2]                             ; Save first free memory address

;   /* Set priority of SWINT to 1. */
    MOV.L    #0x87303, r1
    MOV.L    #1, r2
    MOV.B    r2, [r1]

;   /* Enable SWINT. */
    MOV.L    #0x87203,r1
    MOV.B    [r1], r2
    OR       #(1 << 3), r2
    MOV.B    r2, [r1]

    RTS

    .end